Birthosaur is one of the three skins released under the monthly Skin'O'Matic offer. It could be individually purchased with game coins in late July 2018.
Birthosaur could be purchased in the Skins Shop under the ‘Skin-o-matic’ tab for 1900 coins. This skin was available for a limited time and may not be available for purchase in the future.
Details of this skin may vary depending on location, platform or time.